The usefulness of leptin measurements and ultrasound fat thickness for assessment of body fat reserves of Awassi lambs

摘要

Abstract The objective of this study was to investigate the usefulness of leptin measurements for predicting back fat thickness and the amount of carcase fat in lambs with varying body weights (BWs). Blood samples were taken from 20 male Awassi lambs at 20, 25, 30, 35, and 40?kg BW. Tail, omental, dissected, and total fat were measured at slaughter (40?kg BW). Ultrasound fat thickness (UFT) increased with BW (p?p?=?.09). Serum leptin concentration was correlated with BW for 25, 30, 35, and 40?kg BW (r?=?0.53, 0.52, 0.51 and 0.61, respectively; p?r?=?0.50, 0.51 and 0.59, respectively; p?r?=?0.62, 0.64, 0.66 and 0.76, respectively; p?p?>.05 for 40?kg BW). The introduction of UFT and BW as independent variables in addition to leptin in the multiple regression equations improved the predictions for carcase fat only (57.6%, p??.05; 57.8%, p?p?>?.05 for leptin, leptin?+?UFT and leptin?+?BW, respectively). Leptin was a single predictor for omentum and dissected fat (41.4%, p??.05 and 43.5%, p??.05 respectively) whereas no improvement was observed for tail fat (p?>?.05). The other variables (UFT and BW) were not a predictor (p?>?.05) except for total fat (p?>?.05). These results indicate that serum leptin concentration in association with BW and UFT could be used to estimate total fat (tail, omental and dissectible carcase fat) in male Awassi lambs.